Huidae Cho

@marisn Please try #3440.

> -gf should still work. Ideally, we should make them exclusive in v9.

@echoix I'm not sure about other options for `make` (version 4.3 without `--shuffle` introduced in 4.4), but I just tried ```bash make clean make -j`nproc` ``` It built without errors....

In the manual, > This is an input to r.sun and i.evapo.potrad. It's not clear what `r.sun` expects, edge or center? @YannChemin we need your help.

@wenzeslaus Do you consider adding new `G_OPT_M_PROJECT` and switching to it eventually in GRASS 9?

> Whenever we multiply rows and columns, they should be size_t before multiplication, so the reasoning here fits that. > > Can you provide documentation for size_array while at it?...

Verified identical outputs before and after this PR. For our records, we still have these issues with the -m flag: https://github.com/OSGeo/grass/issues/2222 and https://github.com/OSGeo/grass/pull/2482, but they are not related to this...

> @HuidaeCho Are you planning to merge this PR? Do you know how to re-run *expired* failed tests without making a small commit just to revive them?

> @HuidaeCho would you like to do a rebase for a fresh CI (101 PRs behind), then merge? If I do it I would appear as co-author. This PR looks...

> Are we heading for another field/layer type of confusion? I guess so. In addition, this PR could potentially lead to misleading names of existing "locations" because not all location...